Electron-discharge device



J. A. RADO ELECTRON-DISCHARGE DEVICE Sept. 22, 1959 Filed June 6, 1955 N W i FIG. 2b

FlG.2a

ELECTRON-DISCHARGE DEVICE John A. Rado, West Babylon, N.Y., assignor to Hazeltine Research, Inc., Chicago, 11]., a corporation of Illinois General This invention relates to an electron-discharge device useful for voltage-control purposes and, while of general applicability, it is particularly useful for regulating high voltages of the .order of 10,000 volts and up.

In many applications, particularly in color-television receivers, it is desirable to regulate the high voltage supplied to the final accelerating electrode of the image-reproducing tube or tubes thereof. Such regulation is necessary in color-television receivers in order to prevent un' desirable changes in the luminance component of the reproduced color image. Final electrode accelerating voltages commonly used are in the range of 10,000-30,000 volts.

Previously proposed schemes for regulating high voltin the output level of the high-voltage source.

In many other applications, it is necessary to control the voltage of a circuit supplying either an alternating or a direct-current voltage. Frequently, the systems proposed to control such voltages are either more complex or more unstable than is desirable.

It is an object of the invention, therefore, to provide a new and improved electron-discharge device for controlling the voltage of a voltage-supply means and which avoids one or more of the foregoing limitations of voltage-control systems heretofore proposed.

It is another object of the invention to provide va new and improved electron-discharge device for regulating the output voltage of a high-voltage source. 7

It is a further object of the invention to provide a new and improved electron-discharge device for controlling the voltage of a voltage-suppl y means wherein the Voltage level is determined to a considerable extent by the stable geometric construction of the device.

In accordance with the invention, an electron-discharge device comprises means for producing an electron beam and means for partially intercepting the electron beam. The device also includes an anode for intercepting the. remainder of the electron beam. The device further includes deflection means asymmetrically disposed adjacent and on two sides of the electron-beam path for controlling the proportion, about a mean value, of the electron beam reaching the anode.

Also in accordance with the invention a voltage regulating system comprises circuit means for supplying a voltage which is to be regulated. The system also com- 7 prises an electron-discharge device including means for 0 producing an electron beam, means for partially intertates Patent ice ceptin-g the electron beam and an anode for intercepting the remainder of the electron beam. The system also includes means coupling the electron-discharge device to the voltage supply means to enable the electron-discharge device to load the voltage supply means, and deflecting means asymmetrically disposed adjacent to and on two sides of the electron beam path and coupled to the voltage supply means for controlling, in response to the supply voltage, the proportion, about the mean value, of the electron beam reaching the anode.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawing, and its'scope will be pointed out in the appended claims.

Referring to the drawing:

Eig. '1 is a circuit diagram, partly schematic, of a voltage-supply system including an electron-discharge device constructed in accordance with the present invention, and

Figs. 2a and 2b are plan views of a part of the electrode structure of the Fig. 1 device.

Description of Fig. 1 apparatus Referring to Fig. l of the drawing, there is shown a -voltage-supply system including an electron-discharge device-constructed in accordance with the present invention. The voltage-supply system includes a high-voltage power supply-10 for supplying a high value of output voltage to .a utilization device 11. While the internal circuitry of the power supply 10 may take many different forms, depending on the application and environment thereof, for purposes of explanation the internal circuitry thereof is symbolically represented in the drawing by a resistor 12 and a battery 13. The battery 13 represents a source of voltage and the resistor 12 represents the internal resistance of the power-supply circuit.

Coupled to the connection between the power supply 10 and the utilization device 11 is an electron-discharge device 20, constructed in accordance with the present invention, for controlling the voltage of the voltage-supply means 10. The electron-discharge device 20 includes means for producing an electron beam 30. This means may include, for example, an electron-emissive cathode 21 and a control electrode 22 which are adapted to be connected to suitable sources of operating voltage indicated, respectively, by -B and -C.

The electron-discharge device 20 also includes means for partially intercepting the electron .beam 30. This means comprises, for example, an electrode 24 having an aperture 25 therein which is asymmetrically positioned with respect to the center axis of the electron-beam path. Figs. 2a and 2b show plan views of this electrode for two different positions of the electron beam the cross section of which is indicated by the dashed line circles 30 and 36. The circle 30 of Fig. 2a represents the normally undefiected position of the electron beam at which time the center of the beam coincides with the center axis of the beam path. This view clearly shows the asymmetrical positioning of the aperture 25.

The electron-discharge device 20 further includes an anode 26 for coupling to the voltage-supply means 10 and for intercepting the remainder of the electron beam 30 ,to enable the device 20 to load the voltage-supply means 10. The voltages B and -C are preferably proportioned to produce an electron beam having an intensity sufficient to load the voltage-supply means 10 by a desired amount and to bring the beam to an approximate focus at anode 26. It is preferred that the beam have a cross section comparable to the area of the aperture 25 where it passes through that aperture.

The electron-discharge device 20 additionally includes deflection means disposed adjacent the electron-beam pat-h and adapted to be energized by the voltage of the voltagesupply means 10 to control the proportion of the electron beam 30 reaching the anode 26. This deflection means includes, for example, a pair of deflection electrodes 27 gized by a reference voltage +V for comparing the voltage of the voltage-supply means with the reference voltage +V to control the proportion of the electron beam 30 reaching the anode 26. The deflection electrodes 27 and 28 are preferably positioned intermediate the partially intercepting means 24 and the beam-producing means 21. Alternative locations of the deflection electrodes are feasible, however, and may be desirable in certain applications.

Where, as shown in Fig. 1, the purpose of the device 20 is to regulate a high value of voltage, it is preferable that the voltages supplied to the two deflection electrodes have an unequal effect on the electron beam in order that a low value of reference voltage +V may be utilized on one deflection electrode to balance the high voltage supplied to the other deflection electrode. it is preferable that the deflection electrodes 27 and 28 be asymmetrically. positioned on opposite sides of the electron-beam path, the electrode 28 being the one nearer the beam path and the one to be energized by the reference voltage +V. Asan alternative to this -approach,

an unequal effect on the electron beam may be obtained by making the axial length along the beam path of electrode 28 greater than the corresponding axial length of the high-voltage deflection electrode 27. As indicated by As a result;

the Fig. 1 apparatus, both of these approaches may be utilized in conjunction with one another.

As shown in Fig. 1, it is also preferable to use an accelerating electrode 29 having one end thereof disposed adjacent the beam-producing means 21 for accelerating the electron. beam 30 along the axis of the accelerating' electrode. The accelerating electrode 29, in addition to assisting in the shaping of the electron beam 30, also serves to shield the electron beam. 30 from the undesired influence of stray electrostatic fields over the deflection region thereof, which fields may be particularly troublesome where high voltages are present. Additionally, the accelerating electrode 29 serves as .a support for the intercepting electrode 24 which may be suitably connected thereto.

Instead of using a separate source of reference voltage +V, as shown, it is :feasible to eliminate the deflection" electrode 23 altogether and utilize the wall of the accelcrating electrode 29 or some suitable structure attached thereto as a plane of reference potential. Whether or electrostatic field in the neighborhood of the beam by an amount which varies logarithmically with the length of the tube.

Operation' of Fig. 1 apparatus 2 Considering the operation of the Fig. 1 apparatus just described, the power supply 10 is eifective to supply, for

. example, a high value of direct-current voltage to the.- utilization device 11. At the same time, the cathode 21 of the electron-discharge device 20 is effective to emit I electrons in a'beam which is subsequently attracted to-and shaped by the control electrode 22 and accelerated by In this case, the high-voltage electrode 27 'not this expedient is desirable depends on the type of, voltage being controlled.

the accelerating electrode 29 so as to strike the anode 26. This electron beam constitutes a conduction path across the output terminals of the power supply 10 and,

I hence, serves to load the power supply 10, that is, it serves to draw current from the battery 13. This current, in turn, produces a voltage drop across the resistor 12 so that the output voltage of the power supply 10 is less than what it would be if no such current were flowing therefrom.

In addition to being supplied to the anode 26, the high voltage from the power supply 10 is also supplied to the deflection electrode 27 and, hence, tends to attract .the electronbeam 30 towards this electrode. Under normal or desired operating conditions, however, the electron beam is notdeflected because the reference voltage +V supplied to the deflection electrode28 is tending to attract the beam in a direction opposite to that of the electrode 27. As a result, the center of the electron beam coincides with the center axis of the beam path and, as is indicated in Fig. 2a, half of the electron beam is intercepted by the electrode-24 while the remainder of the. beam passes through the aperture 25 and strikes the anode 26.

Assume now that the output voltage of the power supply 10 falls below the desired voltage level. In this case the voltage supplied to the deflection electrode 27 decreases, thereby enabling the reference voltage on the deflection electrode 28 to pull the electron beam towards supply 10. In this manner, the value of output voltage is increased back to the desired voltage level.

If the output voltage of the power supply 10 should 5 increase above the desired level, then the reverse process occurs, that is, the electron beam is attracted towards the deflection electrode 27 hence increasing the loading 7 on the power supply 10 and thereby decreasing the output voltage.

' It is apparent that the high voltage of the power supply 10 is automatically regulated by the balancing action produced by the reference voltage +V. As a result of the asymmetrical positioning of the deflection electrodes with respect to the electron-beam path and the attenuating effect of tube 31, it is apparent that a low value of ref erence voltage +V may be utilized to regulate a considerably higher value of voltage from the power supply 10. While the reference voltage +V may need to be regulated in order to ensure a high degree of regulation 'of the high voltage, it is a relatively simpler matter to ance with the well-known behavior of a wave guide below cutoff, the attenuating tube 31 is efiective to attenuate the electric field produced at the high-voltage electrode 27 in a logarithmic manner as a function of the length of the tube. In the case of a round tube, it is known that the attenuation effect on the electrostatic field is equal to approximately 21 decibels per radius of tube length, that is, the length of the tube measured in termsof the radius of the tube is efiective to produce an attenuation of21 decibels for each radius of tube length.

In addition to the ratio of length to diameter of the attenuating tube 31, -the relative effect of the high- V r V l voltage field in causing deflection of the electron beam 30 is also dependent on the axial length of the highvoltage electrode 27 relative to the axial length of the reference-voltage electrode 28. In this manner, if the dimension of the deflection electrode 28 along the beam path is twice that of the electrode 27, then the reference voltage +V operates on the beam for a longer length of its travel and, hence, is twice as effective in deflecting the beam. For the relative electrode dimensions shown in Fig. ,1, where the length of the attenuating tube 31 is approximately equal to the diameter of the attenuating tube and the axial length of the deflection electrode 28 is approximately twice the axial length of the deflection electrode 27, a reference voltage of 100 volts is effective to regulate a high voltage of 20,000 volts.

The electrostatic lens produced by the field between electrodes 22 and 29 is utilized to obtain focusing action.

for shaping the electrons emitted from the cathode 21 into the desired electron beam. The shape of the electron beam thus produced is preferably such that its area where it passes through aperture 25 is comparable with that aperture. In some cases, however, it may be desirable to improve the control sensitivity of the electrondischarge device. To achieve this, it appears that a relatively small diameter electron beam may be desirable. The voltage difference between voltages --B and C serves to control the intensity of the electron beam passing through the aperture therein. The intensity of the electron beam, of course, determines the loading on the power supply 10. As a result, by suitably selecting the value of the voltage -C supplied to the electrode 22,

'the intensity of the electronbeam may be adjusted to establish a desired range of control of the output voltage of power supply 10. A specific output voltage may be selected by adjustment of reference voltage +V.

As pointed out in the above example, the electrondischarge device 20 is particularly useful for regulating the output voltage of a high-voltage 'directcurrent power supply. The device 20, however, is not limited to controlling dire-ct-current voltages because it may also be utilized to control alternating-current voltages. In this case, an alternating reference voltage is supplied to the deflection electrode 28. Also, the device 29 is not limited to controlling high voltages because it obviously may be utilized to control low voltages wherever the situation is such as to warrant use of a device of this nature.

As shown in the drawing, the electron-discharge device 20 is used to load down the power supply As an alternative, where the power-supply unit would normally require a rectifier, the device 20 might be used as such rectifier, thus performing both rectifier and regulator functions.

From the foregoing description of the invention, it will be apparent that an electron-discharge device constructed in accordance with the present invention represents a new and improved device for controlling the voltage of voltage-supply means and is particularly useful in regulating the output voltage of a high-voltage power supply.

While there has been described what is at present considered to be the preferred embodiment of this invent-ion, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. An electron-discharge device comprising: means for producing an electron beam; means for partially intercepting the electron beam; an anode for intercepting the remainder of the electron beam; and deflection means asymmetrically disposed adjacent and on two sides of the electron-beam path for controlling the proportion,

'6 about a mean value, of the electron beam reaching the anode.

2. An electron-discharge device comprising: means for producing an electron beam; electrode means having an aperture therein which is asymmetrically positioned with respect to the center axis of the electron-beam path for partially intercepting the electron beam; an anode for intercepting the remainder of the electron beam; and deflection means asymmetrically disposed adjacent and on two sides of the electron-beam path for controlling the proportion, about a mean value, of the electron beam reaching the anode.

3. An electron-discharge device comprising: means for producing an electron beam; means for partially intercepting the electron beam; an anode for intercepting the remainder of the electron beam; and deflection means asymmetrically disposed adjacent and on two sides of the electron-beam path intermediate the partially intercepting means and the beam-producing means for controlling the proportion, about a mean value, of the electron beam reaching the anode.

4. An electron-discharge device for controlling the voltage of voltage-supply means, the device comprising: means for producing an electron beam; means for partially intercepting the electron beam; an anode for coupling to the voltage-supply means and for intercepting the remainder of the electron beam to enable the device to load the voltage-supply means; and deflection means asymmetrically disposed adjacent and on two sides of the electron-beam path and adapted to be energized by the voltage of the voltage-supply means for comparing this voltage with a reference voltage for controlling the proportion, about a mean value, of the electron beam reaching the anode.

5. An electron-discharge device for controlling the voltage of voltage-supply means, the device comprising: means for producing an electron beam; means for partially intercepting the electron beam; an anode for coupling to the voltage-supply means and for intercepting the remainder of the electron beam to enable the device to load the voltage-supply means; and a pair of deflection electrodes asymmetrically disposed adjacent the electronbeam path on opposite sides thereof, one of which is adapted to be energized by the voltage of the voltagesupply means and the other of which is adapted to be energized by a reference voltage for comparing the voltage of the voltage-supply means with the reference voltage to control the proportion of the electron beam reaching the anode.

6. An electron-discharge device for controlling the output voltage of a high-voltage supply means, the device comprising: means for producing an electron beam; means for partially intercepting the electron beam; an anode for coupling to the voltage-supply means and for intercepting the remainder of the electron beam to enable the device to load the voltage-supply means; and a pair of deflection electrodes asymmetrically disposed adjacent the electron-beam path on opposite sides thereof, the farther one of which is adapted to be energized by the output voltage of the high-voltage supply means and the nearer one of which is adapted to be energized by a low-voltage reference voltage for comparing the high voltage with the reference voltage to control the proportion of the electron beam reaching the anode.

7. An electron-discharge device for regulating the output voltage of a high-voltage source, the device comprising: electrode means for producing an electron beam; an accelerating electrode having one end thereof disposed adjacent the beam-producing means for urging the electron beam along the elongated axis thereof; electrode means disposed adjacent the other end of the accelerating electrode for partially intercepting the electron beam; an anode for coupling to the voltage source and for intercepting the remainder of the electron beam to enable the device to load the voltage source; a first deflection electrode located within the accelerating electrode to one side of the electron-beam path and adapted to be energizedlby a low-voltage reference voltage; an attenuating tube having one end thereof connected to a port in the accelerating electrode on the side of-the electron-beam anode and, hence, the loading on the voltage source to reduce changes in the output voltage thereof.

8. A voltage-regulating system comprising: circuit means for supplying a voltage which is to be regulated; and an electron-discharge device including means for producing an electron beam, means for partially intercepting the electron beam, an anode for intercepting the remainder of the electron beam, means coupling the electron-discharge device to the voltage-supply means to enable the electron-discharge device to load the voltagesupply means, and deflecting means asymmetrically disposed adjacent to and on two sides of the electron-beam path and coupled to the voltage-supply means for controlling, in response to the supplied voltage the proportion, about a mean value, of the electron beam reaching the anode.

9. A voltage-regulating system comprising: circuit means for supplying a voltage which is to be regulated; and an electron-discharge device including means for producing an electron beam, electrode means having an aperture therein which is asymmetrically positioned with respect to the center axis of the electron-beam path for partially intercepting the electron beam, an anode for in- I tercepting the remainder of the electron beam, means coupling the electron-discharge device to the voltage-supply means to' enable the electron-discharge device to load the voltage-supply means, and deflecting means asymmetrically disposed adjacent to and on two sides of the electron-beam path and coupled to the voltage-supply means for controlling, in response to the supplied voltage, the proportion, about a mean value, of the electron beam reaching the anode. I

10. A voltage-regulating system comprising: circuit means for supplying a voltage which is to be regulated; and an electron-discharge device including means for producing an electron beam, means for partially intercepting the electron beam, an anode for interceping the remainder of the electron beam, means coupling the electron-discharge device to the voltage-supply means to enable the electron-discharge device to load the voltagesupply means, and deflecting meansasymmetrically dis posed adjacent to and on two sides of the electron-beam path intermediate the partially intercepting means and the beam-producing means and coupled to the voltagesupply means for controlling, in response to the supplied voltage, the proportion, about a mean value, of the electron beam reaching the anode.

11. A voltage-regulating system comprising: circuit means for supplying a voltage which is to be regulated; and an electron-discharge device including means for producing an electron beam, means for partially intercepting the electron beam, an anode for intercepting the remainder of the electron beam, means coupling the electrou-discharge device to the voltage-supply means to enable the electron-discharge device to load the voltage-supply means, and deflecting means asymmetrically disposed adjacent to and on two sides of the electron-beam path and coupled to the voltage-supply means for comparing its voltage with a. reference voltage for controlling, in response to the supplied'voltagethe proportion, about a mean valve,

of the electron beam reaching the anode. Y

remainder of the electron beam, means coupling the electron-discharge device to the voltage-supply means to enable the electron-discharge device to load the voltagesupply means, and a pair of deflection electrodes asymmetrically disposed adjacent to the electron-beam path on opposite sides thereof, one of which is coupled to the voltage-supply means and the'other of which'is coupled to a reference voltage for comparingthe voltage of the voltage-supply means with the reference voltage for controlling, in response to the supplied voltage, the proportion, about a mean value, of the electron-beam reaching the anode. w v

13. A high-voltage-regulating system. COHlPliSiIlgLCifcuit means for supplying a high voltage the output of which is to be regulated; and an electron-discharge device including'means for producing an electron beam,

means for partially'intercepting the electron beam, an anode for intercepting the remainder of the electron beam, means coupling the electron-discharge device to the voltage-supply means to enable the electron-discharge device to load the voltage-supply means, and a pair of deflection electrodes asymmetrically disposed adjacent to the electron-beam path on opposite sides thereof, the further one coupled to the output voltage of the highvoltage-supply means andrthe nearer onegof which is coupled to a low-voltage reference voltage for comparing the high voltage withlthereference voltage to enable the voltage supplied to control the proportion of the electron beam reaching the anode.

14. A voltage-regulating system comprising: circuit means for supplying a voltage which is to be regulated;

and an electron-discharge device including means for producing an electron beam, an accelerating electrode having one end thereof disposed. adjacent the beam-producing means for urging the electron beam along the elongated axis thereof, electrode means disposed adjacent to the other end of the accelerating electrode for partially intercepting the electron beam, an anode for intercepting the remainder of the electron beam, meanslcoupling the electron-discharge device to the voltage-supply means to enable the electron-discharge device to load the voltage supplymeans, a first deflection electrode located within the accelerating electrode to one side of the electronbeam path and coupled to a reference voltage, an. attenuating tube having one end thereof connected to a port in the accelerating electrode on theside of the electron-beam path opposite the first deflection electrode, and a second deflection electrode disposed adjacent to the other end of the attenuating tube, and coupled to the output voltage of the voltage-supply means for comparing the voltage-supply means with the reference voltage to control the proportion of the electron beam reaching the anode and, hence, the loading on the voltage source to reduce changes in the output voltage thereof.

References Cited in the file of this patent UNITED STATES PATENTS Skellett June 7. 1955 ww in. 4.. 

